Processed photographic films and papers which utilize a coupler and a sensitizing dye tend to retain the dye, resulting in staining. This staining tends to be particularly severe with couplers that contain phenol groups or other strong hydrogen bond donor groups. High levels of staining can result in processed papers and reversal films which are visually objectionable, and in negative films with inferior printing characteristics. Consequently, the need exists to identify compositions and methods to reduce retained sensitizing dye and the associated stain.
Sulfoxide groups have been used as coupler substituents. See, for example, Aoki et al. U.S. Pat. No. 4,557,999, issued Dec. 10, 1985, and Sasaki et al. U.S. Pat. No. 4,774,166, issued Sep. 27, 1989. The latter patent also describes sulfoxide-substituted non-coloring phenol compounds.
Use of sulfoxide coupler solvents in combination with couplers is uncommon. U.S. Pat. No. 4,113,488 mentions the use of specific sulfoxides in combination with phenols to improve the light stability of pyrazolone magenta couplers. U.S. Pat. No. 4,419,431 mentions the use of sulfoxides, among other addenda, to improve the light stability of azo dye images.
In commonly-assigned related applications, sulfoxides have been proposed for use in combination with pyrazolotriazole magenta couplers to provide improved photographic speed (U.S. Ser. No. 07/678,427, filed Apr. 1, 1991) and with pyrazolone magenta couplers to provide reduced continued coupling (U.S. Ser. No. 07/689,436, filed Apr. 23, 1991.) Despite the occasional use of sulfoxides in connection with couplers, no reference is made to additional specific coupler solvent-coupler combinations which significantly reduce staining by residual sensitizing dye.